A. Field of the Invention
Apparatus, systems, and methods consistent with the present invention relate generally to supplying power and, more particularly, to apparatus, systems and methods for supplying power in a distributed system.
B. Description of Related Art
Conventional power supply systems for powering distributed systems typically include a main power supply and one or more secondary power supplies. In one type of power supply system, the main power supply receives non-isolated DC power, transforms the DC power, and provides isolated DC power to the secondary power supplies. The secondary power supplies provide the isolated power to respective components of a distributed system.
A drawback of this type of power supply system is that it takes a significant amount of space. The transformer in the main power supply generates significant heat, which must be cooled. This requires the use of large fans and space around the main power supply for airflow.
The air space near the main power supply must be sufficiently large enough to allow airflow across the components. The drag on the airflow caused by the components requires a larger space for the airflow.
A second type of conventional power supply system saves space by removing the transformer from the main power supply. The main power supply provides non-isolated power to the secondary supplies, requiring each secondary power supply to have a transformer for isolating the power from the system elements. Removing the transformer from the main power supply allows it to be housed in a much smaller volume. And it generates less heat, which further reduces the space requirements in the area immediately surrounding the main power supply.
While removing the transformer from the main power supply reduces heat, it does not eliminate the need for significant space. Even though the transformer is removed, the components of a conventional main power supply still generate significant amounts of heat and therefore require significant space for cooling. The removal of the transformer from the main power supply also does not address the need for space caused by the drag.
Therefore, there exists a need for apparatus and methods that supply power in a distributed system without the drawbacks of conventional systems.
Systems and methods consistent with the present invention provide a power supply in a small space. An apparatus consistent with the invention comprises a power receiving element for receiving input power having a first voltage, a power supply for filtering the input power and producing output power having a second voltage slightly lower than the first voltage, and a power supplying element for supplying the output power to a power-isolating element.
Elements of the power supply are optimized electrically so as to minimize the voltage drop between the input of the power supply and the output. Elements are also designed and arranged so as to minimize airflow disruption of airflow across the power supply.
The power supply can be used to power a secondary power supply which powers other components. In one embodiment, the power supply is used in an equipment box to power communications equipment.